Objective: To explore the relationship among self-image, coping style and social support of unmarried young women after radical mastectomy. Methods: A cross-sectional survey was conducted to select 155 young unmarried women after radical mastectomy from three grade-A hospitals in Tianjin. The simplified coping style questionnaire(SCSQ), social support rating scale(SSRS), body image after breast cancer questionnaire (BIBCQ) and self-designed general information questionnaire were used. Results: The self-image score of 155 unmarried young women after radical mastectomy was 150.58±25.22. Self-image was positively correlated with positive coping and social support( P<0.05), and negatively correlated with negative coping（ P<0.05）. Structural equation model analysis showed that social support significantly positively predicted self-image（ β=-0.28, P<0.001）; social support and positive coping（ β=0.40, P<0.001）; positive coping significantly positively predicted self-image( β=-0.14, P=0.019); active coping is a partial mediator between social support and self-image. Conclusion: The self-image level of unmarried young women after radical mastectomy was lower. In order to improve the self-image level and living quality of the patients, we should encourage them to take more positive coping strategies and provide full range of social support in clinical work.